Colour photography



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based on the following general procedure. A photo- 1 graphic silver halide emulsion layer, usually a gelatino silver halide emulsion layer, includes as a uniform dispersion therein, a suitable dyestuff. The layer is exposed to light or otherwise rendered developable so that a latent silver image is formed therein. This image is developed 20 to a silver image. The layer is then treated with a bleach bath which has the efiect of oxidising the silver image and simultaneously reducing (or bleaching) 'the dyestufi in the region of the silver image. The silver salts and any residual silver are then removed from the layer 2 and the layerthen contains only a dyestuff image which is complementary in sign to the original silver image.

Considerable variations are possible in this process.

States PatentO 5 pose. Some hundreds of dyestuifs have been suggested,

but most of the dyestufis proposed are unsatisfactory in one or more respects. A principal difliculty is to ensure that the dyestufi employed will not diffuse from the gelatin emulsion layer in which it is incorporated, and various proposals, such as mordanting, have been made to overcome this difficulty. In selecting dyestulfs for use, moreover, it is desirable that they should be bleached rapidly by the bleaching baths employed and also preferable that their inclusion in the emulsion layer should not too seriously reduce the sensitivity of the emulsion. In addition, of course, it is desirable that the dye should approach as closely as possible to the theoretical requirement that, of red, blue and green light it should absorb all of one while fully transmitting or reflecting both of the others. I

It is an object of the present invention to provide a new class of yellow dyestuffs for use in the silver-dye-bleach process which approach more closely to the desiderata set forth above. 7

According to the present invention a process for the production of a yellow dyestufi image in a photographic layer comprises including in a light-sensitive gelatino silver halide emulsion layer, or in a plain gelatin layer coated adjacent thereto, a yellow dyestuif of the formula:

For example, the layer may be dyed with the dyestulf after the exposure step or after the development of the silver image. Moreover, the dyestutf may be included in a plain gelatin layer coated adjacent to the emulsion layer. A large number of patents have been granted in respect of the process, the main details of which can be ascertained from British patent specification Nos. 397,159 and 397,188.

In order to produce a record in full colour there is generally employed a multilayer material which contains three light-sensitive silver halide emulsion layers, one sensitive to blue light only and the others sensitized to sensitive to blue light only and the other sensitised to layers from recording blue light in addition to the light to which they are sensitised, it is usual to provide a blueabsorbing filter layer between these latter layers and the emulsion which is sensitive only to blue, a common form of assembly being:

(a) Support layer (b) Red-sensitive emulsion layer (c) Green-sensitive emulsion layer (d) Blue-absorbing filter layer (e) Blue-sensitive emulsion layer magenta and layer (e) is dyed yellow. Accordingly,

when the material is exposed, developed to form silver images and subjected to the required bleaching treatment and treated to remove residual silver salts and silver, the final product carries positive yellow, magenta and cyan images complementary to the negative silver images formed on development, so that when viewed it SOaH where X is an unsaturated aliphatic, aromatic or hetero- .cyclic divalent radicle, or of the said formula in which subjecting the developed image to treatment which bleaches or removes the silver image and simultaneously bleaches the dyestuff in situ therewith, and removing any residual silver and silver salts from the product.

The group X may be, for example,

Suitable non-ionogenic substituents are alkyl, e.g. methyl or ethyl, alkoxy, e.g. methoxy or ethoxy, acylamino, e.g. acetylamino groups or halogen atoms, particularly chlorine.

The precise hue of the dyestufi varies with the sub stituents present and their position. Generally, alkyl or alkoxy groups on the intralinear benzene rings in 'meta positionto the azo linkages tend to yield dyes, of more lemon a shade, while the same groups in ortho position to the azo linkages tend to yield dyes of more orange a shade. Halogen atoms in these intralinear benzene groups tend to produce more lemon shades.

Methods for the production of the foregoing class of dyestuifs are exemplified later herein. In general terms they are prepared by diazotising a compound of the formula:

SOQH

(which may contain further, non-ionogenic, substituents),

coupling it with a compound of the formula:

ONE:

(which may contain further, non-ionogenic, substituents) to produce a monoazo dyestufi of the formula:

and treating that dyestufi with an acylating agent of the formula:

Y-CO-X--CO-Y where Y is hydroxyl or halogen, or the two Y groups together represent an oxygen atom, the compound then being an anhydride.

Further, according to the invention a process of colour photography comprises a process as just set forth in which the gelatino silver halide layer is blue-sensitive and constitutes one of the layers of a multilayer photographic material which further contains photographic emulsion layers sensitive to green and red light respectively dyed with magenta and cyan dyestuffs, and the said yellow dyestutf is included in said blue-sensitive layer or in a plain gelatin layer coated adjacent thereto. More particularly the invention provides a process in which the said yellow dyed layer is layer (e) of an assembly consisting of:

(a) Support layer (b) Red-sensitive emulsion layer dyed cyan (c) Green-sensitive emulsion layer dyed magenta (d) Blue-absorbing filter layer (e) Blue-sensitive emulsion layer dyed yellow optionally with plain colloid separating layers between some or all of the adjacent layers recited.

The invention further includes such light-sensitive materials employed in the aforesaid processes, and suitable for variants of those processes, which consist of or include a gelatino silver halide emulsion layer containing a yellow dyestufl. as above set forth.

Specific dyestuffs which have been found to be of particular value are set forth in the examples which follow.

The bleaching of the yellow dyestuffs employed in this invention can be effected by any of the types of bleaching bath commonly employed in the silver-dye-bleach process.

The plain use of acid, e.g. hydrobromic or hydrochloric, is eifective but is very slow. The inclusion of halide salts has an accelerative etfect, but these bleaching baths are still slow. The inclusion of a solvent for silver halide such as thiourea or pyridine has a strongly accelerative effect, and this can be greatly increased by the inclusion of an accelerating substance or catalyst. In these connections reference may be made to British patent specifications Nos. 397,159 and 490,451 for suitable bleaching baths.

The following illustrate suitable dyestuffs according to the invention, and their preparation:

PREPARATION OF THE DYESTUFFS 'Dyestufi N0. 1.--32.1 parts of the aminomonoazo dyestufi obtained by coupling diazotised l-aminobenzene-S- sulphonic acid with 1-amino-2-methoxy-5-methylbenzene, are dissolved at -55 with the addition of sodium carbonate so that the solution has a neutral reaction. After cooling to 20-25, a solution of 11.3 parts of benzenel.4-dicarboxylic acid dichloride in parts of acetone and an aqueous solution of sodium carbonate are so If, in the above example, the components for the formation of the aminomonoazo dyestufi or of the acylating agent are altered according to the following table, then dyestufls are obtained which have similar properties.

Table I Dye- Gelatin Dye- Aqueous Colour of sItIyfi Diazo Component Coupling Component Acylating Agent ing Shade sollution Powder 0, a S ade 2 l-aminobenzene-ii-sulphonie 1-amino-2-methoxy-5-methbenzene 1.3 'carboxylie orange-yellow. orange yellow-brown.

acid. ylbenzene. acid dichloride. 3 do 1-amino-3-acetylam1nobenbenzene 1.4 diearboxylic lemon-yellow" lemon-yellowyellow.

zene. acid dichloride. 4 dn do benzene 1.3 dicarboxylic do yellow yellow-brown.

acid dichloride. 5 do l-amino-zmethoxybenzenen benzene 1.4 dicarboxylic yellow orange-yellow. orange. 6 d 1 3 th 1b actiid dichloride.

o -am no- -me y enzene 0 do do ellow-brown. 7 1-am1no-2 nethylbenze-ne-4 1-aini.no-3-acetylaminoben .do lemon-yell0\v yellow yellow.

sulphonic acid. zene. 1-ammo-4- methylbenzene-2- 1-amino-2-methoxy-5-methdo orange-yellow. orange orange.

sulphonic acid. ylbenzene. l-ammo-3- metl iylbenzene-4- l-amino-3-carbomethoxybenzene 1.3 dicarboxylic lemon-yellow yellow yellow-brown.

sulphonic acid. aminobenzene. acid dichloride. 1-amino-2-n ethoxybenzenel-ammo-3-methylbenzene. benzene 1.4 dicarboxylic yellow do yellow.

5-sulphon1c acid. acid dichloride. l-ammo-3-methoxybenzene- 1-amino-2-meth0xybenzene- -do orange-yellow. orange orange.

4-sulphonic acid. l'amino-zA-dimethylben- 1-amino-3-carbomethoxyyellow orange-yellow- Do.

ZGH G-G-SHIDhODIG acid. aminobenzene. l-ammo-et-chlorobenzene-5- l-amino-3-acetylaminoben- .do do yellow yellow-brown. 1 sulphoric glcidb 2 zone.

-ami.no- -c oro enzenedn do lemonellow lmon- 11 W sulphonic acid. y 6 ye 0 yellow l-ammo-4- methylbenzene-2- do do yellow yellow D0.

sulphonic acid. 1-amino4-hydroxybenzenel-aminoi-methylbem do orange-yelloworange orange.

S-carboxylic acid-5-sulphonic acid. 17 l-ammobenzenee-sulphonic l-amino-3-methoxybenzene 2.5-dich1orohenzene-1A-diyellow yellow yellow-brown.

ac carboxylic acid dichloride. 18 l-arninobenzene-tsulphonic 1-am ino-3-carbomethoxydo lemon-yellow do yellow.

aci ammobenzene.

2,899,305 I s e Dyestufi N0. 19.-33.4 parts of the aminomonazo dyee are dissolved neutral in 500 parts of water with sodium stufi 1-arnino-benzene-4-sulphonic acid l-amino-3-actylcarbonate. 8.5 parts of furnaric acid dichloride diluted aminobenzene are dissolved with a neutral reaction with with 50 parts of benzene and an aqueous solution of sothe addition of sodium hydroxide in 500 parts of water. dium carbonate are so added dropwise simultaneously at 11.4 parts of pyridine-2.5-dicarbxylic acid dichloride dis- 5 30-35 that the reaction mixture always has a neutral resolved in 60 parts of dioxan are slowly added dropwise at action. On completion of the dropwise addition, the re- 40-45". The hydrochloric acid which is split off during action mixture is stirred until no more free amine can the reaction is continuously made neutral by the simultabe traced. The disazo dyestulf of the formula:

C 3 s CH3 CH which is obtained is precipitated by the addition of sodium chloride, filtered off and washed with diluted sodium chloride solution. The dried dyestuff is a yellow powder neous addition dropwise of caustic soda lye. As soon as no more aminomonoazo dyestufi can be traced, the disazo dyestuff formed is precipitated by the addition of sodium chloride, filtered off and washed with diluted sodium chloride solution. After drying, it is a yellow-brown powder which dissolves in water with a yellow colour and dyes gelatin in lemon-yellow shades. The new dyewhich dissolves in water with a yellow colour and has a very good aflinity to gelatin.

stuff corresponds to the formula; If, in the above example, the 8.5 parts of fumaric acid no.s -N=N@-Nn-c 0-( 0 O-N HQN=N- -s 0 H N NH-r-CO-OHg NH-C 0-4211,

It, in the above example, the 33.2 parts of the aminodichloride are replaced by the corresponding number of monoazo dyestufi are replaced by a corresponding numparts of maleic acid dichloride, methyl fumaric acid di- P 9 the E dyesmlfs glven "H116 chloride, methyl maleic acid dichloride, bromofumaric following table, or if the acylatmg agent is replaced by hl M f m a corresponding number of parts of one of the acid c onde butadl-ene" l.4-dicarboxylic acid dichloride, or if the 305 parts of the halides given in the following table, then dyestuffs are obtained which have similar properties. 40 aminomonoazo dyestuff are replaced by the correspond- Table II Gelatin Dye- Aqueous Colour of stufi Diazo Component Coupling Component Acylating Agent ing Shade Solution Powder N 0. Shade 20 l-aminobenzenei-sulphonic 1-amino-2-methoxy-5-methylpyridine-2.5-dica.rboxylic acid orange-yelloworangeuv red-orange.

aci benzene. dichloride. 21 l-aniiinobenzeue-ti-sulphonic l-amino3-methylbenzene pydritlline-ai i-diearboxylic acid lemon-yellow" yellow yellow.

aci ic ori e. 22 do 1-amino-3-acetylaminobenpyridine-2.6-dicarboxylic acid -do do Do,

zene. dichloride. 1-aminobenzene-2-Su1ph0nie 1-amino-2-methoxybenzene. pyiidhipe-iiddicarboxylic acid yellow do Do.

ac c ori e. 1-amino-2-methy1benzene-4- 1 -amino -3- carbomethoxypyridine-2.4-dicarboxylic acid do do D0.

sulphonic acid. aminobenzene. dichloride. 1-amino-4-methylbeuzene-2- l-amino-3-methoxybenzene thiophene-2.5-dicarboxylic acid. orangc-yellow orange orange.

sulphonic acid. dichloride. 1-amino-3-methylbenzene-4- l-aruino-Qmethoxy-fi-methylthiophene-2.4-diearboxylic acid orange do red.

sulphonic acid. benzene. dichloride. 1-amino-2-methoxybenzene-5- 1 amino 3 carbornethoxythiophene-2.S-dicarboxylic acid orange-yellow. -do yellow-brown. sulphonic acid. aminobcnzene. dichlor' e. 1-amino-3-methoxybenzene-4- 1-amino-3-methylbenzene. IuIan-2.5-dicarboxylic acid diyellow yellow yellow.

'sulphonic acid. chloride. 1amino-5chlorobenzene-2-sull-amino-2-methylbenzene.. furan-2.5-dicarboxylic acid lemon-yellow-- do yellow-brown.

phonic acid. chloride. 1-amino-4-hydroxybenzene-3e 1-amino-3qnethylbenzene. pyrrole-Zj-dicarboxylic acid orange orange red.

carboxylic aeid-5-su1phonic dichloride. acid.

ing number of parts of one of the aminomonoazo dyestufis listed in the following table, then dyestuffs with similar properties are obtained.

In the following table, fumaric acid dichloride is used as acylating agent in each case.

Dyestufi N0. 31.30.5 parts of the aminomonoazo dyestuff of the formula:

Table III Dyestufi Gelatin Dyeing Aqueous Colour of N o. Diazo Component Coupling Component Shade Sglpton Powder l-amino 4'methylbenzene-2-sulphonic acid l-amino-B-acetylaminobenzene yellow yellow-- orange.

l-amino-3-methylbenzenei-sulphonic acid l-amino-Z-methoxybenzene lemon-yellow do yellow.

l-aminobenzene-3-sulphonic acid 1-amino-2-methyl-5-acetylaminobenzene yellow do. Do.

. do l-amino-3-acetylami.nobenzene .do "do-.." Do.

l-aminobcnzene-Z-sulphonic aeid l-arnino-2-methoxy-5-methylbenzeneorange-yellow. range red-orange.

do l-amino-3'carbomethoxyaminobenzene. lemon-yellow" yellow yellow.

l-amino-2-n1cthoxybenzene-5sulphonie acid. l-amino-2-methoxy-fi-methylbenzcneorange-yellow. orange orange.

1-amino-3-metlioxybenzene-4-sulphonic acid. l-amino-B-methylbenzene yellow yellowyellow-brown. 1a1n1ino-2.4-dimethylbenzene-6-sulphon.ic o lemon-yellow.. do..- yellow.

aci l-amino-4-ehlorobenzene-5-su.lphonic acid l-amino-3-methoxybemene do do Do. 1-amino-5-ehlorobenzene z sulphonic acid. l-amino-Z-methoxy-S-acetylaminobenzcne orange-yellow. orange red. 1-amino-4-hydroxybenzene-3-carboxylic 1-amino-3-metliylben ene do do yellow-brown acid--sulphonic acid.

Dyestufl N0. 44.36.5 parts of the aminomonoazo The dried coating is exposed to light to record an image dyestufi obtained by coupling diazotised l-amino-4- therein and processed at 68 F. as follows:

ethoxybenzene-Z-sulphonic acid with l-amino-Z-methoxy- S-methylbenzene are dissolved with a neutral reaction in 500 parts of water with the addition of sodium hydroxide. 11.3 parts of benzene-1.4-dicarboxylic acid dichloride dissolved in 200 com. of acetone are added dropwise through one dropping funnel and simultaneously an aqueous solution of sodium hydroxide is added through another dropping funnel, both additions being made at 2025 within 1 hour in such a way that the reaction mixture has always a neutral reaction. As soon as no more aminomonoazo dyestufi can be traced, the disazo dyestuff formed is precipitated by the addition of sodium chloride, filtered 01f, washed with diluted sodium chloride solution and dried.

The new dyestuff corresponds to the formulas OCH;

It is a brown-red powder which dissolves in water with an (1) Develop to a silver image by two minutes treatment in the following developer:

Metol gm 0.75 Sodium sulphite, cryst gm 25 Hydroquinone gm 3 Sodium carbonate, cryst gm Potassium bromide gm 1 Water to 1 litre.

30 (2) Rinse 30 seconds.

(3) Fix in 20% sodium thiosulphate for 3 minutes. (4) Rinse 30 seconds.

(5) Harden in 4% formalin.

(6) Wash 10 minutes.

(7) Dye bleach for 8 minutes in the following bath:

orange-red colour and it dyes gelatin in orange-yellow Hydrochloric id (311 1 19) 100 Shades- Potassium bromide gm 12.5 Similar dyestuffs are obtained if, in the above example, Thiourea gm 10 equivalent amounts of the compounds listed 1n the follow- 2; 3-dim th 1 quinoxaline gm 0,1 ing table are used as components for the formation of the Wat t 1 lit aminomonoazo dyestuff and as acylating agents: (8) Wash 5 minutes.

Table IV Dyestufi Diazo Component Coupling Component Acylatiug Agent Gelatin Dyeing Aqueous Solu- Colour of N o. Shade tion Shade Powder 45 l-aminol-hydroxybenzeuel-amino-B-acetylaminobenbenzene 1.4 dicarboxyllc orange orange-red"..- yellow-brown.

3 carboxylic acid 5 sul zene. acid dichloride. phonic acid. 46 l-aminobenzene-S-sulphonic l-amino-2-methoxy-5-methpyridine 2.5 dicarboxylic yellow-orange. orange red.

acid. ylbenzene. acid dichloride. 47 l-ominol-methoxybenzenedo benzene 1.4 dicarboxylic orange orange-red... Do.

2-sulphonic acid. acid dichloride. 48 l-arnino-Z-methoxybenzenelo do do yellowish red yellow-brown.

5-sulphonic acid.

The following example, which for simplicity is concerned only with the treatment of a single layer containing the yellow dyestuff, will serve to illustrate the invention:

4.38 gms. of dyestufi No. 1 above and 3.3 gms. of

EXAMPLE (9) Silver bleach for 5 minutes in the following bath:

Copper sulphate, cryst gm 100 Sodium chloride gm 100 Hydrochloric acid, conc cc 50 Water to 1 litre.

(10) Wash 5 minutes.

(11) Fix in 20% sodium thiosulphate for 3 minutes. (12) Wash for 10 minutes and dry. A reverse image in dye is obtained.

Steps 4 and 5 may be omitted if the original emulsion is hardened or provided with a hardened gelatin supercoat.

Similar results are obtained using the other dyestuffs the bridging group X, developing said image, subjecting falling within the formula stated. When the process is the developed silver image to treatment which bleaches repeated with a similar, but undyed, silver halide emulthe silver image and simultaneously bleaches the dyestufi sion, supercoated on the dyed emulsion, it is found by in situ therewith, and removing any residual silver and microscopic examination that substantially none of the 5 silver salts from the product.

dyestufi? in the dyed layer migrates to the undyed layer 2. A light-sensitive gelatino silver halide emulsion coneither on coating the film or on processing. taining a yellow dyestuff selected from the class consisting All the said dyestulfs are of satisfactory hue, have very of dyestuffs of the formula:

SOQH SO H good resistance to migration, bleach rapidly and etfecwhere X is selected from the class consisting of divalent tively, and are generally of exceptional value in the silverethylenlcally ullsablllated p fadlcles, Phenylene dy b1 h process f colour photography Those dyes radicles and unsaturated divalent heterocyclic radicles,

dyestufis of the said formula in which the various benzene rings carry substituents selected from the class consisting of alkyl groups, alkoxy groups, acylamino groups and which absorb more in the visible spectrum, i.e. which appear more orange in colour, are preferred since it is generally possible to obtain adequate image density using a lesser amount of such dyes than is necessary when the ktlhalogen 5 and dye-stuffs oithe Said formlljla g lemomyenow dyes are used e termlna enzene r ngs eac carry one car oxy 1c acl group, the dyestufis belng symmetrical about the bridging What we claim is: group Process the Production of a Yellow dyestufl 3. A light-sensitive gelatino silver halide emulsion conimage 1n a photographic layer which comprises forming a taining the yellow dyestufi of the formula:

I l I 80 11 NHOOOH NHCOCH 803E latent image in a light-sensitive gelatino silver halide emul- 4. A light-sensitive gelatino silver halide emulsion consion layer containing a yellow dyestuif selected from the taining the yellow dyestufl of the formula:

(I) CH3 0 CH3 O:H N= NHG OOO ONHQN= Q0 (hm soar: 0H; CH SO H class consisting of dyestuffs of the formula: 5. A light-sensitive gelatino silver halide emulsion con- Q =N-C NHO O-X-C ONH N=N- 0,13. 80,11

where X is selected from the class consisting of divalent taining the yellow dyestutf of the formula:

N=NQNH CO GO NHQN=NQ 0311 on, H, 0,13:

ethylenically unsaturated aliphatic radicles, phenylene References Cited in the file of this patent radicles and unsaturated divalent heterocyclic radicles, UNITED STATES PATENTS dyestulfs of the said formula in which the various ben- 2 304 884 Carrol Dec 15 1942 zene rings carry substituents selected from the class con- 2326055 Morris g 1943 sisting of alkyl groups, alkoxy groups, acylamino groups 2i673:198 Grandjean et a1 Man 1954 and halogen atoms and dyestuffs of the said formula in which the terminal benzene rings each carry one car- FOREIGN PATENTS boxylic acid group, the dyestufis being symmetrical about 522,241 Canada Feb. 28, 1956 

1. A PROCESS FOR THE PRODUCTION OF A YELLOW DYESTUFF IMAGE IN A PHOTOGRAPHIC LAYER WHICH COMPRISES FORMING A LATENT IMAGE IN A LIGHT-SENSITIVE GELATINO SILVER HALIDE EMULSION LAYER CONTAINING A YELLOW DYESTUFF SELECTED FROM THE CLASS CONSISTING OF DYESTUFFS OF THE FORMULA: 